Vaporizing pot type burner



March 4, 1958 H. M. RE-EVES ETAL 2,825,399

VAPORIZING POT TYPE BURNER Filed 001?. l, 1954 31 22am 257:5 $4EBBEBT PLBEEvEs JAMEs E. NOBTH EARL D. H/LLEBBAND rates 2,825,399 VATORIZING PSTTYPE BURNER Application October 1, 1954, Serial No. 459,792 2 Claims.(Cl. 158-91) The present invention relates in generalto liquid fuelburners and, more particularly, to vaporizing pot type burners whichfind use, for example, in oil burning stoves and furnaces.

The general aim of the invention is to make possible improved andsmoothly variable control of the rate of fuel combustion in pot typeburners, giving infinitely fine adjustment between the limits of a pilotflame and the maximum high fire flame for which the burner is designed.

Further to that aim, it is an object of the invention to provide animproved pot type burner wherein the exposed surface area of liquid fuelis automatically varied with the rate of fuel feed, the rate ofvaporization and combustion thus being smoothly controllable.

Another object of the invention is to provide an improved burner inwhich time lag in the response of flame height to changes in fuel feedrate is drastically reduced.

Still another object is to provide such a burner in which runaway actiondoes not take place, the liquid fuel being partially shielded from theheat of a high flame. Radiated heat from the flame aids in producing thevaporization necessary for the maximum flame, but unduly greatvaporization is prevented.

A further object is to provide such a burner which is of simple andeconomical construction, reliable in operation, and readiiy dismantledfor cleaning purposes.

Other objects and advantages of the invention will become apparent asthe following description proceeds, taken in conjunction with thefollowing drawings, in

which:

Figure l is a vertical section of a pot type burner embodying thefeatures of the invention;

Fig. 2 is a bottom plan View of the pilot housing empioycd in the burnerof Figure l; and V Fig. 3 is a detailed view in section showing themanner in which the burner pot is supported.

While the invention has been shown and is described in some detail withreference to a particular embodiment thereof, there is no intention thatit thus be limited to such detail. On the contrary, it is intended hereto cover all modifications, equivalents, and alternative constructionsfalling within the spirit and scope of the invention as defined by theappended claims.

Referring now to the drawing, a pot type burner it) here illustrated asan exemplary embodiment of the invention, comprises generally a pot 11which, in this instance, is substantially in the shape of a cylinder.The pot is formed of very similar upper and lower sheet metal halves11a, 11b which may be formed to their approximate shapes by the samedies on a metal press, and then finished to their individualconfigurations. A simple interlocking seam at 12 tightly fixes the twohalves together. For supplying primary air to the upper portion of thepot, its side Walls are made perforate, that is, formed with a pluralityof holes 14 arranged in vertically spaced rows. Primary air is suppliedto the bottom portion of the pot through a plurality of holes 15 formedat a downwardly directed angle in an inturned bead 16. The air enteringthose holes naturally flows downwardly to strike the surfaces of liquidfuel present in the bottom of the pot, thus readily causing thenecessary vaporization.

The upper end of the pct 11 is formed with a large central outletopening 13 and means are provided for mounting the entire pot in amanner such that the opening 18 is alined with a matching opening 19 ina supporting partition 20. The partition'20 and the top of the pot 11are shaped and interrelated to define a passage through which secondaryair is supplied to and mixed with fuel vapor rising from the interior ofthe pot in a manner to promote efficient combustion of the fuel. As hereshown, the pot 11 is suspended from the apertured partition 20 which, inturn, is fixed, as by welding at its periphery, in a casing 21 definingthe main combustion chamber at 22. Self-tapping screws 24, insertedthrough the partition 20 at points spaced around the opening 19, areengaged with matching holes 25 in the top of the pot. The pot 11 and thepartition 20 are curved to define an upwardly and inwardly taperingpassage 26 terminating in an annular port 28 just above the opening 18.In this manner, secondary air is drawn up through the annular spacebetween the side walls of the pot 11 and the casing 21, the velocity ofsuch air being increased in the tapering passage 26 so that the air isthrown horizontally into the rising vapors and mixes thoroughly with thelatter. Accurate spacing of the pct 11 and partition 20, and thusaccurate determination of the area of the port 28 is achieved by theprovision of a series of downturned tabs 29 formed in the partition. Thescrews 24 are merely tightened until the top of the pot is drawn firmlyagainst the tabs 29, the dimension of the port 23 thus being accuratelydetermined each time that the parts are assembled.

In liquid fuel burners of the general type described, the problem ofcontrolling flame height and resultant heat presents real difliculty.Once vaporization and burning of liquid fuel in the bottom of the pot isinitiated, the heat supplied by the small flame produces progressivelygreater vaporization and burning so that without some special provision,a runaway action occurs. While various attempts have been made in thepast to solve these difficulties and while some prior proposals haveresulted in burners which would successfully hold a small pilot flame,none is known which permits perfectly smooth adjustment of the flamelevel between a pilot flame and the maximum heat for which the burner isdesigned.

In accordance with the invention, the difficulty is solved by so formingthe bottom of the pot 11 that the exposed surfaces of liquid fuelsupplied thereto varies smoothly and proportionally in area with theamount of the fuel present. In addition, means are provided such that apart of the exposed surface of liquid fuel is subject to directradiation and heating from a flame in the upper part of the pot onlywhen there is a relatively great amount of fuel present and a high flameis desired.

In the present instance this is accomplished by crowning the bottom 30of the pot l1 upwardly at its central portion 30a. That is, the potbottom is formed in a generally upwardly concave shape so that a smallamount of fuel present in the pot bottom lies in an annular ring and asmore fuel is added, it progresses inwardly toward the pot center, thusexposing a proportionally greater surface area from which vaporizationmay take place. It will be noted that in order to obtain the maximumadvantage of the invention, the pot bottom should smoothly rise from itslowest level at the periphery to its highest level at the centralportion so that the exposed surface area of liquid fuel is a directfunction of the amount of fuel present.

ass-5,399

puddle beneath said ring, and at higher feed rates lies in ReferencesCited in the file of this patent a puddle of greater area extending intosaid housing, T D TAT P T whereby at such higher feed rates said ringshields a por- UNI E S ES A ENTS tion of the fuel in the pot bottom fromhigh flames in 2,369,999 Behrendt et 1945 th ti f th t t I. v m u dul ta2,466,563 Stempel et a1. Apr. 5, 1949 j ggfi gf fif f F e e n y 52,535,923 Hill Dec. 26, 1950

